The cranial halo was first reported by Perry and Nickel in 1959. (Perry J., Nickel V. L., Total Cervical Spine Fusion for Neck Paralysis, J. Bone Joint Surg. 1959; 41A:37.) Since then, it has become widely accepted for a secured fixation and versatility. The halo may be utilized to provide skeletal traction for the entire spine, and combined with a cast or a vest it provides the best available external control of cervical spine instability. Control adjustments may be made for traction, angulation, rotation, and translation. Once locked into position, the halo vest or halo cast will prevent over 95% of the cervical spine motion in all planes; a degree of rigidity far superior to that provided by conventional orthoses. (Johnson, R. M., Hart, D. L., Simmons, E. F., Armsby, G. R., Southwick, W. O., Cervical Orthoses, J. Bone Joint Surg. 1977; 59A:322.)
Unfortunately, the significant advantages of this halo have been partially offset by the difficulties in its application. Initially published methods for applying the halo (Nickel, D. L., Perry, J., Garrett, A., Application of the Halo, Orthat. Prosthet. 1960; pp. 31-35, and Young, R., Thomassen, E. H., Step By Step Procedure for Applying the Halo Ring, Orthop. Rev., 1974; 3(6):62-64) have been cumbersome and time-consuming in practice. By these methods, the patient's head is either hand-held or precariously supported on a narrow board, and the halo ring is supported by yet another pair of hands and a set of positioning pins and plates. The lack of rigidity makes exact positioning of the ring difficult to obtain. Recently, a report by Weiss and Wilmot describes a device which supports the head during halo application, but their device does not support the halo ring and can only be used with a patient on a Stryker frame. (Weiss, M. S., Wilmot, C. B., Head Positioning Device for Applying Halo Traction, Arch. Phys. Med. Rehabil., 1981; 62:89.) The present invention, known as the Hershey Halo Jig (Trade mark), was developed to increase the speed, accuracy, and safety of the halo application. This device has been used successfully on an experimental basis at the Milton S. Hershey Medical Center since the first prototype was developed in March 1979. Over this period of time, a number of variations have been made based upon experimental usage and experience. The present invention constitutes the final design, as presently contemplated, of this improved halo jig.